Ambrose, Timothy, author
Routledge , 1995
Buku Teks
Woo, Kyu Sung, author
Rockport Publishers, 1999
Buku Teks
Edwards, Edward, author
Thoemmes Press, 1996
Buku Referensi
Miguel Galas, 1970
Buku Teks
Faika Rahima Zoraida, author
Fakultas Eknonomi dan Bisnis Universitas Indonesia, 2010
UI - Tesis (Open)